Get ready for a game-changing upgrade! We're introducing a full moto style axle block system and axle to our MX and SX bolt-on extension. This enhancement will not only allow you to adjust your chain tension with ease and precision, but it will also solve the common problems of chains falling, bouncing around, and the noise from the chain tensioner. No more compromises, just smooth, efficient, and quiet performance. This extension is designed as a 2-3 inch stretch which matches perfectly with our new 630mm fork kit to create a balanced and more stable ride. This length gives the bike some much needed stability but doesn’t take all of the fun out of riding by still giving you a manageable balance point. Compatibility MX500, MX650 & SX500 ONLY Specifications Material: 6061 Billet Aluminum Manufacturing Process: CNC Extension Length: 2-3 inches Axle: 12mm with Axle Blocks Fits: MX500, MX650, SX500 Drilling your stock swing arm is required.